Nutrient supplementation of water flood oil recovery processes has been shown to be effective in conventional water injection implemented as a means of secondary and tertiary recovery. This invention relates to the process of using resident microorganisms in the geologic oil formation to assist in oil recovery to improve oil production rate and ultimate recovery from the oil reservoir. The invention uses an unconventional method using low concentrations and controlled volume and rate of injection of nutrient materials through periodic nutrient supplementation of water injection through wells that are structurally located near the top of the oil producing rock formation to take advantage of gravity to disperse the nutrients downward through the oil bearing strata. Once the nutrient materials are injected into selected wells, gravity causes the injected water-nutrient mixture to percolate downward, driven by specific gravity differences between the injected nutrient mixture and the oil contained in the reservoir thus increasing the effectiveness of the distribution of the nutrients. The addition of nutrient and subsequent nutrient deprivation stimulates resident microorganisms to change both physiologically and metabolically resulting in specific groups of microbes becoming interactive with the oil in the reservoir leading to changes to the flow characteristics of the oil contained in the oil-bearing strata. Once released, this oil can then be produced in nearby oil production wells or from the well where the injection of nutrients took place utilizing a cyclic process consisting of an alternating and repeating, inject, produce, inject, produce sequences. This invention contemplates both a novel injection site and a novel nutrient distribution method to improve the stimulation of resident microorganisms in an oil reservoir to increase the recovery of oil.
An objective of the present invention is to provide a method of improving oil recovery through the use of a nutrient package and gravity dispersion.
Another objective of the present invention is to provide a method of improving oil recovery in oil containing rock formations.
These and other objectives will be apparent to those of ordinary skill in the art based upon the following written description, drawing and claims.